Cal and Stanford football: Big Game in October? What the heck …

* Grades for the Bay Area schools are coming in the next 18 hours, as usual.

* The following story, which appears in Monday’s Mercury News and Bay Area News Group papers, is intended to explain why Big Game is being playing in October.

Much of the information below was reported on the Hotline last winter, when the date was announced. But if you missed the story back then, here are the details …

The Big Game is less than a week away.

Yes, it’s October.

Yes, it’s weird.

Cal and Stanford have met 114 times since 1892, with all but a few games in late November. Three have been played in early December. None have been played in October, until now.

“It’s just not natural when you’ve been doing it for so long at a certain time,” Cal coach Jeff Tedford said of Saturday’s showdown in Berkeley.

The odd timing couldn’t be avoided. The Pac-12 has limited scheduling flexibility because of a confluence of factors, including:

* The conference championship game, established last year, occupies the first weekend in December — a window previously used by some schools for their final game.

* USC and Stanford play Notre Dame on the Saturday after Thanksgiving (in alternating years), thus leaving UCLA and Cal in a bind.

* The increased number of Thursday night games (more broadcast windows mean more television dollars). Per league policy, Thursday participants must have a bye the previous Saturday.

Working within those parameters, the conference presented three schedule models for the 2012 season to the schools last fall.

The first, which placed the Big Game on the Saturday after Thanksgiving, was rejected by Cal and Stanford because of concerns that the holiday weekend would conflict with events associated with the game.

The second model, which placed the Big Game on the Saturday before Thanksgiving, was rejected by the rest of the conference because of strains it placed on other facets of the schedule.

The third model, which slotted the Big Game on Oct. 20, was approved by the league as a whole and forced upon the Bay Area schools.

“Cal and Stanford were clear that they did not want to play the Big Game Thanksgiving week,” Pac-12 commissioner Larry Scott explained when the October date was first announced. “We presented additional options to our member institutions for discussion and a vote. Ultimately, the majority vote determined the schedule.”

The good news for Big Game traditionalists is that an October affair won’t happen again, at least for a few years.

When the football season has 15 Saturdays — as it does in 2013 and ’14 — there’s enough flexibility for every Pac-12 rivalry game to be played in late November.

But in 2015, the Saturday squeeze returns. At least one rivalry will be moved off a traditional weekend.

“The burden will be shared around the conference,” deputy commissioner Kevin Weiberg said. “Once a rivalry game has been impacted one time, it won’t come around again until others have been similarly impacted.”

For Tedford, one time is too many.

“This is getting a little bit out of hand,” he said. “Traditions are not even thought of anymore.”